The Lost
by StripedFuzzySocks
Summary: "To Leo, the news came as a slap in the face. Literally." In the aftermath of Marcus' death, Leo is forced to be Caitlin's lab partner while Bree is away at camp. But even more chilling is the dark truth he unwittingly discovers on her laptop - a story of betrayal, illusion, and duplicity... a story of love. MAREE. Now a T rated 2-shot.
1. Part I

**Disclaimer: I do not own Lab Rats or any other Disney owned mention, only this FanFic which belongs to ME. © StripedFuzzySocks**

**A/N: Okay, the secret's out. I ship Maree. While I probably (definitely) don't think they could make it work on the actual show because they didn't pursue it to begin with (a stupid move really), I find it incredibly interesting in the world of Fan Fiction where anything can, will, and does happen. I rated this story M because it has sexual references and a few 'morning after' scenes (nothing gross or physical though), thus taking a very different toll from any of my previous stories. It actually may even have a theme against teen sex, if you squint hard enough. I've never written romance before because I think I'm bad at it, but with the novel I'm writing, there is romance and I thought I could use the practice. And what better way to do that than with a short Maree story? There aren't near enough good ones out there and I haven't contributed to this fandom in awhile. And so, here I am.**

**The prologue doesn't have Marcus or Bree in it at all. XD What it is is basically the aftermath of their relationship and Bionic Showdown where Marcus dies... *tear*... from Leo's POV. Pretty much the rest of the story is told in flashbacks and the epilogue in real time. Without further ado, enjoy!**

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Prologue

**Of Stalkers and Secrets**

...

For Leo, the news came as a slap in the face. Literally.

It was Chemistry, the last class of the day, and Leo was exhausted and just waiting to go home already. Glancing up from the cartoon doodles in the margins of his notes, a small smile grew on his face as he read the clock. Only three more minutes and he was out of there. Ms. Lentz continued to teach, but Leo was finding it increasing difficult to concentrate when Spark Man's cape needed shading in.

Absorbed in his drawing, Leo let out a not-so-manly screech in response to the bell that set off a chorus of mocking laughter throughout the classroom. Blushing red, he could hear his classmate's whispers as they brushed past him on their way out. So much for climbing the social ladder. Suddenly, Leo got another surprise when Ms. Lentz came right up to his desk and started taking. To him. To _Leo_. Oh, gosh. She didn't see him drawing in class, did she? His assigned seat was all the way in the back of the room!

It was one of the few things he actually enjoyed about this disaster of a semester in Chemistry. The disaster part was a _long _story, to be continued later. Realizing he was zoning again, Leo snapped his attention back to his teacher, who had gone silent in obvious seething rage. He gave her a nervous smile.

"Leo, I need you to pay attention to me when I'm talking to you. I hope you're not this distracted when you're supposed to be taking notes." She huffed, offended.

"No, not at all! Today's lesson was very… interesting." Leo groped for the right word. Ms. Lentz seemed to accept his cover, and he sighed with weak relief inside.

"That's good to hear, because we will be having a note check tomorrow and I look forward to seeing how much you retained." She answered evenly, a sly smile creeping its way onto her thickly layered lip gloss. Darn. He should've known it wasn't that easy. But that was what bionic brothers with super smarts were for. Check and mate.

"Awesome!" Leo exclaimed as convincingly as he possibly could, slinging his backpack over his shoulder to follow his classmates out. But to his third surprise, Ms. Lentz laughed good-naturedly and ushered him back into the classroom, even though it was now empty. Well, almost empty… Caitlin stood bored on the other side of the room, waiting for them. Now Leo was more confused than ever.

"I didn't come over here to talk to you about your note taking skills, Leo. I'm sure you already heard about that tragic accident with Marcus…" Her voice trailed as she seemed to be fighting tears, but Leo couldn't even force himself to look solemn.

Or effected at all, really. At least not in the way she would expect after a "tragic death of a beloved classmate and friend". What a load of crap. Marcus was a two-faced liar who had turned his own siblings against him and tormented him daily. He tried to capture Adam, Bree, and Chase (actually he succeeded…) and nearly wiped them all out. Off the top of his head, Leo could count four attempts on his life, and that was being generous. Marcus wasn't even _human_. And yet, every day at school was another day of solemn, mourning faces shaken with grief for the kid they never even knew. To Leo, it almost seemed unfair that a creature so horrifying evil be remembered so dearly. To the people around him, Marcus was a sweet, harmless, and friendly but socially awkward kid killed in a car crash riding home from school. It just wasn't _fair_, was all. Even after death, Marcus had everyone fooled.

Ms. Lentz lightly brushed a tear away, breaking Leo out of his thoughts. He remembered to look sad when he nodded.

"Well, he _was_ your lab partner, but with an entire semester of projects ahead of us, we need to find you a replacement. So, with Bree away at cheer camp this week, I've temporarily paired you with Caitlin, seeing as she is the only other student without a partner." She announced, motioning Caitlin over from her reluctant spot by the whiteboard. Leo's eyes flew open in undisguised terror. Oh, no. Oh, no. Oh, _heck _no!

"Don't worry, she may be a grade older than you, but she's one of my best students and I'm sure she'll be of great help with the research paper due next Monday. You'll get along fine." Ms. Lentz smiled warmly and left them alone in the classroom.

Caitlin narrowed her eyes, looking him up and down. He gulped.

"You're Adam and Chase's brother, right?" She asked suddenly. Leo nodded wordlessly, afraid to croak in front of Madame Straightjacket. With psychos, you just never know. An unholy sadistic grin slowly grew on her face, making Leo want to shrink through the floor into a bottomless hole where Caitlin couldn't look at him like that. Because that, he knew, was her idea face.

"Sweet. We'll meet at your house today to work on the paper. Right after school?" She immediately proposed. Desperately, Leo scrambled to come up with an excuse for her not to come – something, _anything_, but all he could do under her impatiently waiting gaze was stutter illegibly.

"I'll take those animal noises as a yes. _It's a date._" Caitlin emphasized the ending and exited the room like a professional villain.

The second she was out of range, Leo let out the huge gulp of air he had been holding, barely resisting the urge to shiver. His skin was practically crawling with her lingering presence and he couldn't believe he had just invited that _in his house_. In his _house_ with his two brothers who happened to be the newest targets for her creepy obsession. Leo sighed when he finally dared to leave. Even with that creep Marcus gone, it seemed like there would always be someone after his siblings. They just could not catch a break.

And to make matters worse, Bree was out of town, and therefore unavailable to wrangle her best friend out of stalking. For some reason, she seemed to be the only person in the entire school (maybe the entire world) who could somewhat control Caitlin. She could still definitely give Norman Bates a run for his money, but it was slightly less… _extreme_ in Bree's presence for some reason unknown to man. But with her gone, it was as if all heck had broken loose, and she was back on the prowl. So, you can only imagine Leo's horror at the idea of spending hours in the same room with her while he can only cringe as she gives his brothers that look and maybe, if she's feeling extra psycho stalker, go through their backpacks looking for DNA samples. Yeah, she went there.

But seriously, Bree has been away for two days now and it's like every time Leo's seen her she's gotten more unhinged, if that's physically possible. For the first time since Adam, Bree, and Chase were kidnapped by that megalomaniac Douglas, he felt true, pulsing fear for his sibling's safety. Sure, they _were_ bionic and powerful, but if he'd learned anything from watching Cops; if there's a will, there's a way and no one has more will to do it with them than Caitlin.

* * *

When the doorbell rang, Leo screamed at the top of his lungs, earning disturbed looks from Adam and Chase where they sat on the couch watching TV. They must have come home before he could warn them, Leo frantically pieced together. He hadn't the slightest clue how Caitlin was able to get here so fast, but none of that mattered now. He had to stop this! Pointing with his arm outstretched at the door, Leo's throat ran dry with unintelligent squealing sounds.

"What is it, Lassie? Timmy's stuck in the well?!" Chase mocked while Adam laughed. Before he could respond, fists banged on the door, shaking the house. A voice called out next - a voice that haunted Leo's nightmares, shutting everyone up immediately.

"Open the door, Leo! I know you're in there! I just saw you walk in!" Caitlin's voice rang through the door as paralyzing as the Grim Reaper himself.

Leo whipped his gaze back to Adam and Chase, who had bolted upright in pulsing fear. Leo mouthed _run_ to them, but the gesture was wasted as they were already tearing across the living room, where they almost ran over each other to press the elevator button. It was then that the door burst open on its own, sending Leo into a screaming fit. _Seriously, why can't I just _once_ scream like a dude?_ Leo managed to think through the terror. Caitlin raised an eyebrow at him, but seemed to dismiss his behavior almost immediately. She scanned the room behind him, but eventually turned her disappointed gaze back to Leo.

"Leo, do you know where Adam and Chase are? I mean, I don't want to disturb them or anything..." She quickly justified, but Leo knew exactly what she wanted to say and sent a silent thanks to the universe that they got out in time. Now if only Leo could be so lucky...

"Sorry, but I think they went out. You know, we could always do this on Google Docs." Leo suggested. Caitlin shrugged bored-like, the previous sparkle in her eyes back when there was hope she could 'run into' my brothers gone.

"Well, I'm already here. We might as well do the research together." She said as she plopped onto the couch and pulled out a laptop. Leo was about to join her when a sudden, disturbing thought popped into his head.

"Um, Caitlin?" He started shakily, causing her to look at him expectantly. "How were you able to open the door? It was locked."

For a second, her face was flushed a panicked red, sending a cold chill down Leo's spine, but she quickly composed herself.

"There was a key under the 'Welcome' mat. It really wasn't that hard." She explained haughtily.

"And you couldn't just wait for _me_ to open the door...?" Leo pressed, a sick feeling festering in his stomach.

"This paper is due on _Monday_! The sooner we get started, the better!" Caitlin was practically yelling in defense now.

"Okay, okay. Fine! Let's get working!" Leo held his hands up in surrender, making his way to the chair on the far opposite her.

But as he walked behind her laptop, he saw a picture pop up that stopped him dead in his tracks. And it wasn't the kind of picture you would expect to be scarred for life by on Caitlin laptop; for example, it wasn't hideously vulgar, or even Adam or Chase in the boy's locker room. And yet, it made Leo's blood run cold and his heart skip a beat (and not in the supposed good way). Blown up on Caitlin's screen was Marcus and Bree looking the happiest he'd ever seen either of them. They obviously didn't know their picture was being taken at the time, as Marcus' face was turned away from the camera and buried in Bree's hair, appearing to be whispering something in her ear.

Bree's eyes were shut tight, a broad grin played upon her face as she nearly doubled over in laughter. The short, navy dress she wore to the Homecoming dance swayed at her knees, slightly blurred from movement. Other kids danced around them, but Bree and Marcus were the only ones in focus. This must have been taken before it all happened. Leo's blood boiled at the betrayal all over again, feeling almost faint as his eyes landed on the picture's center. Marcus' arms were wrapped around Bree's waist - not her shoulders or her stomach, but her _waist_, his hands resting naturally on her hips. She didn't seem to mind. She didn't seem to care. To Leo, it almost looked like... she _liked _it.

"LEO! Oh my god! Are you okay?!" Caitlin's voice called out in the distance.

The ceiling spun before Leo's eyes, the hazy colors dancing in his vision. He didn't know he had ended up on the floor, but frankly, he didn't care. All he could see was that image flashing over and over again in his mind - _his_ hands around her waist. His sister's waist! That gleam of mischief in his eyes... the way he looked at her... the way she didn't care, she didn't even care! Leo's breathing was rapid now and he vaguely recalled the words _panic attack _before a sting of pain exploded across the side of his face, snapping him out of his trance. He instinctively shot to his feet, a hand reaching up to caress the hit area. Leo returned Caitlin's worried expression with an accusing glare, quickly piecing together her slapping him right across the face.

"What? It always works in the movies." She defended herself.

Leo took another deep, shaky breath as he slowly began to recompose himself. Sinking down into the chair he was aiming for earlier, he forced himself to think it through. He must've just been reaching behind her to get something, like money from someone else's purse, for example. Leo wouldn't put it past Marcus to pickpocket. Actually, Leo wouldn't put anything past Marcus. That kid gave 'amoral' an entirely new definition. He only saw the picture for a few seconds anyway, it was likely he had read it wrong. After all, there's no way _that _could be right. Even before his siblings discovered Marcus' true intentions, Bree was never really close to him. If anything, he was just her brothers' friend that she tolerated. That was all. Still...

"Uh, Leo? Are you okay yet, because I found this really good website that can classify the organisms for us in Study Hall and -," Caitlin's voice trailed in exasperation to see her lab partner still in shock. "Leo, come on! We're doing this together and you can't get out of it by faking a panic attack."

"Wh-why did you... where did that take that... wh-what - when was that?" Leo managed to stumble. Caitlin looked on unimpressed.

"In Study Hall. I just told you." She said simply, crossing her arms. Leo shook his head furiously to try and think straight.

"No, no not that. The picture. You had it pulled up on your laptop." Leo explained. Caitlin frowned, confused, until recognition lit her eyes.

"The one I took at Homecoming? With Marcus and Bree in it?" She asked. Leo nodded. "What about it?"

"Just... explain it to me." It was the best he could come up with.

"Um, okay. I was walking around with my camera; I saw them together and thought they looked cute, so I snapped a pic. Happy now?" She shot back tensely, shifting uncomfortably in her seat. Leo narrowed his eyes suspiciously.

"But what was going on in there? What were they doing?" He pressed on desperately.

"Dancing. Why do you care so much anyways?" Caitlin turned the conversation back to him.

"Looked like more than dancing to me." Leo said it outright, his voice gaining a new steely edge to it.

"Look, Leo. I don't know what to tell you. They were two friends out having a little fun. Big whoop." She practically growled this time.

"No, there was something else there. Caitlin, what do you know?" He begged her now.

"It's not my place to say." She replied stubbornly.

"Please, she's my sister!" Leo continued relentlessly.

"If Bree really wanted you to know, she would have told you." She argued still, but I knew enough now to figure it out myself.

"They were a couple, weren't they?" Leo pieced together, feeling bile rising in his throat. Caitlin sighed in defeat and closed her laptop, turning to face him.

"Leo, they were never a couple. They were hardly friends. Marcus treated her like total trash, stringing her along for weeks before he finally broke her heart for good. Then he had to go and die. The last thing Bree needs right now is you interrogating her about her love life. Just leave her alone about this, okay?" Caitlin begged. Leo was glad to be sitting down for this new wave of shock, because his mind could barely register this.

The two sat in silence for a few minutes before Leo finally spoke up.

"I want to know what they did. I want to know everything. I don't care how bad it is." He demanded fiercely.

"Trust me, you don't." Caitlin shook her head sadly.

"_Please._" He pressed. The rest of the afternoon they spent enveloped in what felt like a Greek tragedy...

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**A/N: Be sure to leave a review telling me what you think (you have no idea how much it makes my day). (: Thanks for reading,**

**-StripedFuzzySocks-**


	2. Part II

**Disclaimer: I do not own Lab Rats or any other Disney owned mention, only this FanFic which belongs to ME. © StripedFuzzySocks**

**A/N: Hey, I kind of feel like a jerk for saying this, but I'm ending the story now even though only one chapter was posted. It's not because I don't have interest or ideas or even enough fans, but because I had an epiphany. This whole story could so easily be converted to its own novel that I could actually publish, and I'm now seriously warming up to the money version - I'm almost done mapping it out. I wish I could tell you more details, but that's pretty much all there is to it. This wasn't all that popular on Fan Fiction, so at least I won't be letting down that many people, but to the followers - bless you all - I can at least post what I had written before my epiphany, as a means of a 1,750 worded goodbye present. (:**

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Part I

**Even the Odds**

**Bree**

I was seriously ticked off. No, ticked off wouldn't be fair to describe the searing, burning frustration I felt that day it began. I had just _had it_. Totally had it. No more. I was so sick and tired of running around trying to do the right thing while Leo went crossing every line, pushing every button, and bending every rule made the farthest it would stretch - and the little weasel _got away with it_. Every freaking time. And yet it was me sitting here outside the principal's office like a criminal when I did nothing wrong! The more I thought about it, the more it just made my blood boil at the injustice.

All this time I spent trying to be a good sister, trying to give Leo a chance to come clean, and look where it got me. I was so enveloped in my own quickly escalating thoughts, I didn't even notice the figure sliding into the seat next to mine until a blurred hand waved across my face, jerking me back to the present. Surprised, I turned to my right to meet the friendly face of Marcus and relaxed slightly.

"Oh, hey, Marcus. I didn't see you there." I apologized sweetly, nervously brushing a lock of brown hair behind my ear. God, it was so humiliating to be sitting on the bench outside the office where _everyone _could see you. And now Marcus knew I was here too. Even better.

"Hey, it's cool." He brushed it off naturally, leaning back in the seat. "So, how did you end up here? I had no idea you were such a rebel under all that pink." He joked, but at the same time seemed genuinely confused.

"I'm not!" I shot back a little too fiercely. "I mean, it's not my fault I'm in here. I didn't do anything wrong."

"Okay, now I have to ask. What happened?" Marcus implored. I sighed and shook my head in exasperation, crossing my arms in stead of replying immediately.

"Forget it. Your little friend Leo will probably tell you all about it later, about how I'm the biggest jerk on the planet." I huffed, admittedly with sass. Something I said must have pricked his interest, because Marcus then straightened in his seat slightly with a new spark in his gaze.

"We're actually not that close." He corrected me with that cool nonchalance of his.

Blushing, I suddenly remembered the great guitar incident of Career Day and the bitter rivalry the two (or primarily Leo) had for each other since then, every nasty look and snide remark washing back. Sometimes I tended to dump all my brothers into one category and didn't really bother to keep tabs on the little things, but for Marcus' sake, I could have at least taken the liberty to remember the fact that Leo wanted him to die in a fiery explosion. Yes, he really did say those exact words.

"Oh, right. Well, it's really no big deal." I assured him as sweetly as I could, my gaze wandering down to my sneakers.

"It was a big enough deal for you to be sent to the principal's office." Marcus commented dryly.

"Why do you care so much anyways?" I asked, truly wondering. He was my brothers' friend, after all. Why should he care about me?

"Just curious..." His voice trailed, then perked to its usual friendly aura. "And it looks like you could use someone to vent your frustrations on."

We sat in silence for a moment while I paused in hesitation, deciding whether or not to even get into it, but eventually my patience broke and I knew I had to vent to someone before I exploded.

"Alright, fine. Here it is. Leo was up all last night playing with his stupid spy cam and filming me in my sleep - creepy, right? And _that's _not even what I'm mad about! After an entire day of following me around school with that thing, he has the nerve to think I'd let him copy off my test for the Semester Exam! So of course I said I wouldn't - that would be cheating. But he used it to copy my answers anyway and when I got up to stop him, Perry flunked me for leaving my seat." I finished, my anger slowly beginning to simmer down from talking.

I let out a breath and nervously searched Marcus' face for a reaction, but his returning gaze revealed nothing apart from a guarded thoughtful expression.

"So, if your punishment was failing the test, then why are you here?" He asked.

"Um..." I laughed anxiously and broke the eye contact. "I _may _have been less than cooperative when Perry kicked me out..."

"What did you do?" A wide, amused grin spread on Marcus' flawless features, giving him a darker kind of happy than I was used to seeing.

"I - I talked back." I answered quickly, feeling my cheeks burn red. "I mean, I didn't say anything bad, but I think I caught her on a particularly evil day - even more than usual. Again, here I am." I finished with a sweeping motion to the bench.

"So, you're mad because Leo cheated off your test." Marcus summed up simply.

"Well, yeah... but what really bugs me is that he always gets away with that kind of stuff. It's not just this, either - it's all the time, with everything." I explained.

"So, you're mad because Leo cheated off your test and didn't get caught." He looked to me for clarification.

"Pretty much." I nodded, feeling that answer to be more right.

"Why?" He asked. I returned his waiting gaze with a shocked one.

"Well, why should he get to cheat when everyone else has to do the work?" I shot back.

"You could cheat." Marcus proposed. I was lost under his chocolate brown stare, tongue tied in his words.

"No, I'd get caught." I scrambled for the words.

"So this isn't really about Leo at all, is it?" Marcus grinned a one-sided smile, taking in my confusion with the new blissful but dark undertone I had never seen in him before now. I don't know why, but I almost found myself wanting more of it. This was a difference from the winy, awkward kid I thought he was the day I met him. This was a nice difference.

"Huh?" I managed to respond finally.

"Your problem is you." He announced boldly.

"Excuse me?" I protested, just starting to find my footing in the conversation again.

"Maybe you should worry less about what your brothers are doing, and more on what you're doing." Marcus suggested.

"And what do you suggest I do? Cheat? Break the rules?" I asked breathlessly, once more lost in his trance.

Marcus smiled a small, suggesting smile and leaned in close, until I was sure he was going to try to kiss me, but no. His lips paused inches from mine, frozen as though in a tease. A very, very small part of me recognized my ability to move away, but I don't think I could. I was already enraptured; intrigued. Even then, I couldn't move if I wanted to. Which I didn't. I really didn't want to. Face to face we remained, my eyes locked in his and his in mine. Did he want this? I couldn't tell - his expression was a closed book and his eyes revealed nothing but dark temptation.

"What do _you_ want to do?" He whispered, his quiet tone deathly serious.

There was no trace of humor anymore, and he waited with endless patience for my response. The world dulled in the background and all I could see was him - his eyes, his look, his face, his _lips_ waiting. Waiting for me. In that tense moment, I didn't feel myself at all. I just heard Marcus' words coursing through me over and over. I could do anything I wanted right now. Right now I had the power to change everything. No one had to decide for me anymore if I didn't choose to let them. The only reason people walked all over me was because _I _let him. Not anymore. I cleared my mind of all thoughts, living out every second of the encounter as if it stretched into a sweet lifetime all its own. I closed my eyes and leaned into it, feeling our lips connect perfectly in sync, like we shared the same thoughts, moved under the same mind.

Continuing without hesitation, in the back of my head I vaguely conceived the kiss deepening and growing more intense, but that only made me more desperate not to break the spell. My heart was beating so hard against my chest it made me wonder if Marcus could feel it too, we were pressed so close now. I didn't know what was going on, or what I was doing. I didn't even know if I was supposed to care or not. Internally, I decided that these were afterthoughts I would have to deal with when I got home, and for now to live in the moment as if it could last forever. I only wished it could last forever. _What better eternity was there?_ I drunkenly pondered. My mind was mush, held captive by the moment. I no longer wanted to spoil it with thoughts. Unconsciously drawing closer, if that was possible, I put my head at rest, letting it slip below my now erupting fireworks of emotions.

I honestly don't know what would have happened next had it not been for the harsh pop pierce sharply through my ears, causing the hairs on the back of my neck to stiffen in surprise. My lips froze and I grudgingly pulled away, utterly breathless and lost in a daze. I felt like I just got hit by a meteor. _The best kind of meteor..._

"Hey, Little Miss! If you're done swapping spit, your parents are waiting in my office right now!" Principal Perry barked from the office doorway.

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**A/N: Ha ha... I had way too much fun writing that... Well, I hope you enjoyed it! XD**

**Keep Calm and Write On,**

**-StripedFuzzySocks-**


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